A practical method for determining the accuracy of computer-generated holograms for off-axis aspheric surfaces

Li, Shijie; Liu, Bingcai; Tian, Anmin; Guo, Zhongda; Yang, Pengfei; Zhang, Jin

doi:10.1016/j.optlaseng.2015.08.009

Cited by 11 publications

(8 citation statements)

References 10 publications

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“…2. The focus 0 I of the transmission sphere is first imaged to 1 I by CGH (the first subsystem), then 1 I is imaged to 2 I by the testing part (the second subsystem), and 2 I is finally imaged to 3 I by the CGH again (the third subsystem). For convenience in discussing the disturbed area on CGH, we assume the exit pupil of the CGH null system is placed on CGH in the image space of the third subsystem.…”

Section: The Aberration Model In Seidel Formalismmentioning

confidence: 99%

“…The focal lengths of the first and third subsystems are determined by the diffraction order and the added optical path of CGH phase function. For the diffraction orders ( + 1, + 1), 3 I is the perfect image of 0 I and coincides with 0 I , which can be used to gain the added optical path of CGH phase function in the following discussion. …”

Section: The Aberration Model In Seidel Formalismmentioning

confidence: 99%

“…It is easy to see the 3rd-order distortion calculated by our aberration model agrees well with the actual distortion. In addition, there are two different 3 x corresponding to the same 3 x , which means two rays pass through the exit pupil at the same 3 x . This is also the reason why we find two ray errors at one 3 x in Fig.…”

Section: Casementioning

confidence: 99%

“…1(c) x in case 3. The ray error and 3 x are the X-axis coordinates of the real ray on equivalent pinhole filter and on the CGH in the second pass, respectively.…”

Section: Casementioning

confidence: 99%

“…However, since aspheric surface is not self-collimated under spherical wavefront, i.e., the testing rays do not impinge normally on aspheric part, it cannot be directly tested under standard interferometer. Computer-generated hologram (CGH) is often inserted between the aspheric part and the transmission sphere to transfer spherical wavefront to match the aspheric one [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Analysis of spurious diffraction orders of computer-generated hologram in symmetric aspheric metrology

He¹,

Hou²,

Wu³

et al. 2017

Opt. Express

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Abstract:Computer-generated hologram (CGH) has been widely used as a wavefront compensator in symmetric aspheric metrology. As a diffractive element, it generates different diffraction orders, but only the 1st-order diffraction is used to test aspheric surface. The light from spurious diffraction orders (SDO) will produce many high-frequency fringes in interferogram and reduce measurement accuracy. In this paper, we regard the CGH null system as an imaging system and develop an aberration model in Seidel formalism to analyze the SDO. This model has the advantage to address the difference between the SDO (k 1 , k 2 ) and (k 2 , k 1 ). We consider the effect of the pupil distortion so that our model can analyze the SDO with a large pupil distortion. We derive the condition to ensure the 2 nd -order and 4 th -order aberrations have the same sign and calculate the minimum defocused distance (power carrier frequency) of CGH. According to the marginal-ray heights ( 1 h and 3 h ) on the CGH in the first and second passes, we determine the condition that the SDO covers the whole CGH in the second pass. We analyze the SDO of 4 CGH designs and compare the results from our aberration model with these from real ray trace. These results validate that our aberration model is feasible whether the aspheric part is convex or concave and whether CGH is inside or outside the focus of the transmission sphere.

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Section: The Aberration Model In Seidel Formalismmentioning

confidence: 99%

Section: The Aberration Model In Seidel Formalismmentioning

confidence: 99%

Section: Casementioning

confidence: 99%

“…1(c) x in case 3. The ray error and 3 x are the X-axis coordinates of the real ray on equivalent pinhole filter and on the CGH in the second pass, respectively.…”

Section: Casementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Analysis of spurious diffraction orders of computer-generated hologram in symmetric aspheric metrology

He¹,

Hou²,

Wu³

et al. 2017

Opt. Express

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show abstract

A flexible angle compensation method for freeform surface testing based on tip/tilt mirror

Gao

Shen

et al. 2019

Optics Communications

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Foveated near-eye display using computational holography

Cem

Hedili

Ulusoy

et al. 2020

Sci Rep

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Holographic display is the only technology that can offer true 3D with all the required depth cues. Holographic head-worn displays (HWD) can provide continuous depth planes with the correct stereoscopic disparity for a comfortable 3D experience. Existing HWD approaches have small field-of-view (FOV) and small exit pupil size, which are limited by the spatial light modulator (SLM). Conventional holographic HWDs are limited to about 20° × 11° FOV using a 4 K SLM panel and have fixed FOV. We present a new optical architecture that can overcome those limitations and substantially extend the FOV supported by the SLM. Our architecture, which does not contain any moving parts, automatically follows the gaze of the viewer’s pupil. Moreover, it mimics human vision by providing varying resolution across the FOV resulting in better utilization of the available space-bandwidth product of the SLM. We propose a system that can provide 28° × 28° instantaneous FOV within an extended FOV (the field of view that is covered by steering the instantaneous FOV in space) of 60° × 40° using a 4 K SLM, effectively providing a total enhancement of > 3 × in instantaneous FOV area, > 10 × in extended FOV area and the space-bandwidth product. We demonstrated 20° × 20° instantaneous FOV and 40° × 20° extended FOV in the experiments.

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A practical method for determining the accuracy of computer-generated holograms for off-axis aspheric surfaces

Cited by 11 publications

References 10 publications

Analysis of spurious diffraction orders of computer-generated hologram in symmetric aspheric metrology

Analysis of spurious diffraction orders of computer-generated hologram in symmetric aspheric metrology

A flexible angle compensation method for freeform surface testing based on tip/tilt mirror

Foveated near-eye display using computational holography

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